The goal of our research is to increase our understanding of the normal and abnormal function of the cardiovascular and cardiopulmonary systems and to improve the accuracy of diagnosis and the effectiveness of treatment of cardiovascular and cardiopulmonary disease. We plan to accomplish this by studies on the physiology and pharmacology of the cardiovascular and cardiopulmonary systems of experimental animals and man which emphasize disease-induced changes in performance and in response to drugs. The research which we plan to conduct can be subdivided into six closely related Missions which emphasize the following areas and topics: 1. The physioloical basis for disturbances in the electrical and mechanical activity of the heart and the action of cardiac drugs. 2. The role of the autonomic nervous system in cardiovascular regulation and its importance in cardiovascular disease. 3. The pharmacology and toxicology of antiarrhythmic agents and the diagnosis and medical treatment of arrhythmias in patients with coronary artery disease. 4. Improved diagnosis and surgical treatment of patients with congenital and acquired heart disease and their complications. 5. Studies in the Surgical Research Laboratories on cardiovascular physiology and pharmacology. 6. Correlations between ultrastructure and electrophysiology of cardiac tissue. 7. Pediatric Cardiac Electrophysiology and Pharmacology. These six Missions are supported by a single Core facility which provides essential services to all investigators.